In ordinary man, organic quiet is scarcely ever complete during sleep; the brain, as we shall see shortly, automatically repeats the vibrations which normal consciousness has called forth during the waking state; this, together with an habitual density of the nervous elements, too great to respond to the higher vibration, explains the rarity and the confused state of the impression of astral consciousness on the brain.
The facts relating to the higher consciousness are as numerous as they are varied. We shall not enter into full details, but choose only a few phenomena quoted in well-known works.
Manifestations of the Higher Consciousness During the Different Kinds of Sleep.
Normal dream. During normal sleep there exists a special consciousness which must not be confounded either with waking consciousness or with that of the astral body. It is due to the automatic, cerebral vibration which continues during sleep, and which the soul examines on its return to the body—when awake. This dream is generally an absurd one, and the reason the dreamer notices it only on awaking is that he is absent from the visible body during sleep.
The proof of the departure of the astral body during sleep has been ascertained by a certain number of seers, but the absurdity of the commonplace dream is a rational proof thereof, one which must here be mentioned. As another rational proof of the existence of a second vehicle of consciousness, we must also notice the regular registering of the commonplace dream, because it takes place in the brain, and the habitual non-registering of the true dream experience, because this latter takes place in the externalised astral body.
Why does the astral body leave the physical during sleep? This question is beyond our power to answer, though a few considerations on this point may be advanced.
Sleep is characterised by the transfer of consciousness from the physical to the astral body; this transfer seems to take place normally under the influence of bodily fatigue. After the day's activity, the senses no longer afford keen sensations, and as it is the energy of these sensations that keeps the consciousness "centred" in the brain[5]; this consciousness, when the senses are lulled to sleep, centres in the finer body, which then leaves the physical body with a slight shock.
It is, however, of the real dream—which is at times so intelligent that it has been called lucid, and at all events is reasonable, logical, and co-ordinate—that we wish to speak. In most cases this dream consists of a series of thoughts due to the soul in action in the astral body; it is sometimes the result of seeing mental pictures of the future[6] or else it represents quite another form of animistic activity, as circumstances and the degree of the dreamer's development permit.
It is in the lucid dream—whether belonging to normal or to abnormal sleep—that occur those numerous and well-known cases of visions past or future to be found in so many of the books dealing with this special subject.